Brief Article
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World J Hepatol. Sep 27, 2013; 5(9): 505-512
Published online Sep 27, 2013. doi: 10.4254/wjh.v5.i9.505
Changes of liver fat content and transaminases in obese children after 12-mo nutritional intervention
Elvira Verduci, Carlo Pozzato, Giuseppe Banderali, Giovanni Radaelli, Chiara Arrizza, Antonio Rovere, Enrica Riva, Marcello Giovannini
Elvira Verduci, Giuseppe Banderali, Giovanni Radaelli, Chiara Arrizza, Enrica Riva, Marcello Giovannini, Department of Pediatrics, San Paolo Hospital, University of Milan, 20142 Milan, Italy
Carlo Pozzato, Antonio Rovere, Department of Radiology, San Paolo Hospital, 20142 Milan, Italy
Giovanni Radaelli, Unit of Medical Statistics, San Paolo Hospital, University of Milan, 20142 Milan, Italy
Author contributions: Verduci E, Pozzato C, Banderali G, Arrizza C and Rovere A contributed to direct participation in the study, including substantial contributions to conception and design of study, or acquisition of data, or analysis and interpretation of data, or supportive contributions; Verduci E, Pozzato C, Riva E and Giovannini M contributed to manuscript writing, including drafting the article, or revising it critically for intellectual content; Radaelli G contributed to supportive work, including statistical analysis of data and interpretation.
Correspondence to: Elvira Verduci, PhD, Department of Pediatrics, San Paolo Hospital, University of Milan, Via A Di Rudinì 8, 20142 Milan, Italy.
Telephone: +39-2-89159414 Fax: +39-2-39561536
Received: May 1, 2013
Revised: August 2, 2013
Accepted: August 16, 2013
Published online: September 27, 2013

AIM: To assess a relationship between longitudinal changes in liver fat content and biochemical parameters in obese children after 1-year nutritional intervention.

METHODS: Forty-six obese children, 21 males and 25 females, aged 6-14 years, underwent metabolic measurements, liver ultrasonography (US) and chemical-shift magnetic resonance imaging (MRI) examinations at baseline and after 1-year nutritional intervention. A child was defined obese if her/his body mass index (BMI) was above the age- and sex-adjusted BMI Cole’s curve passing through the cut-off of 30 kg/m2 at 18 years. BMI Z scores were calculated and adjusted for age and gender by using the Cole’s LMS-method and Italian reference data. Biochemistry included serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Abdominal US and chemical-shift MRI were performed according to a randomized sequence. The same radiologist performed US by a GE Logiq 9 (General Electric Healthcare Medical Systems, Milwaukee, WI, United States) using a 3.5-MHz convex array transducer. Liver echogenicity was evaluated independently on videotape by 3 radiologists unaware of the child and MRI outcomes, and a consensus was established. Another experienced radiologist, unaware of the child and US data, performed the abdominal chemical-shift MRI with a 1-t system NT-Intera (Philips Medical Systems, Best, The Netherlands) and a phased-array coil. Liver fat fraction (FF) on MRI was judged elevated when greater than 9%. A FF > 18% was considered expressing more severe cases of fatty liver according to Fishbein. A nutritional-behavioral intervention was recommended to promote a normocaloric balanced diet and active lifestyle based on the Italian guidelines for treatment of childhood obesity.

RESULTS: Compared to baseline, at the end of intervention children showed lower intakes of energy (mean ± SD: 2549 ± 1238 Kcal vs 1770 ± 622 Kcal, P < 0.0001), total fat (90 ± 47 g vs 52 ± 23 g, P < 0.0001), carbohydrates (356 ± 174 g vs 241 ± 111 g, P = 0.001), and protein (99 ± 48 g vs 75 ± 23 g, P = 0.006) intakes. Prevalence of FF ≥ 9% declined from 34.8% to 8.7% (P < 0.01), with a mean reduction of 7.8% (95%CI: 5.0-10.6). At baseline, FF was associated with liver biochemical parameters (maximum P < 0.001). At the end of the intervention association was found with AST (P = 0.017). Change of FF was associated with change in AST (P = 0.027) and ALT (P = 0.024). Rate of increased liver echogenicity declined from 45.6% to 21.7% (P < 0.0001). Liver echogenicity was associated with ALT at baseline only (P < 0.001). An age- and sex- adjusted multiple regression analysis showed that FF change was independently associated with change in serum AST (adjusted regression coefficient 0.348, P = 0.048).

CONCLUSION: The results suggest that in obese children longitudinal changes in liver fat content based on MRI may be associated with change in serum transaminases suggesting novelty in monitoring nonalcoholic fatty liver disease.

Keywords: Nonalcoholic fatty liver disease, Childhood obesity, Serum transaminases, Magnetic resonance imaging, Nutritional intervention

Core tip: In our study we demonstrate that in obese children longitudinal change in liver fat content evaluated on magnetic resonance imaging is associated with change in serum transaminases and more weakly also with changes in triglyceridemia and apolipoproteins, after a nutritional intervention based on normocaloric balanced diet. Furthemore this is the first study purposely designed to evaluate in obese children whether any relationship may exist of longitudinal changes in liver fat content with changes in liver biochemical parameters These findings may suggest novelty in clinical monitoring nonalcoholic fatty liver disease severity in childhood obesity.